Coarse woody debris: Managing benefits and fire hazard in the recovering forest

Management of coarse woody debris following fire requires consideration of its positive and negative values. The ecological benefits of coarse woody debris and fire hazard considerations are summarized. This paper presents recommendations for desired ranges of coarse woody debris. Example simulations illustrate changes in debris over time and with varying management

Local environment of Nitrogen in GaN{y}As{1-y} epilayers on GaAs (001) studied using X-ray absorption near edge spectroscopy

X-ray absorption near-edge spectroscopy (XANES) is used to study the N environment in bulk GaN and in GaN{y}As{1-y} epilayers on GaAs (001), for y \~5%. Density-functional optimized structures were used to predict XANES via multiple-scattering theory. We obtain striking agreement for pure GaN. An alloy model with nitrogen pairs on Ga accurately predicts the threshold energy, the width of the XANES ``white line'', and features above threshold, for the given X-ray polarization. The presence of N-pairs may point to a role for molecular N_2 in epitaxial growth kinetics.Comment: Four pages (PRL style) with two figure

Langevin Simulation of Thermally Activated Magnetization Reversal in Nanoscale Pillars

Numerical solutions of the Landau-Lifshitz-Gilbert micromagnetic model incorporating thermal fluctuations and dipole-dipole interactions (calculated by the Fast Multipole Method) are presented for systems composed of nanoscale iron pillars of dimension 9 nm x 9 nm x 150 nm. Hysteresis loops generated under sinusoidally varying fields are obtained, while the coercive field is estimated to be 1979 $\pm$ 14 Oe using linear field sweeps at T=0 K. Thermal effects are essential to the relaxation of magnetization trapped in a metastable orientation, such as happens after a rapid reversal of an external magnetic field less than the coercive value. The distribution of switching times is compared to a simple analytic theory that describes reversal with nucleation at the ends of the nanomagnets. Results are also presented for arrays of nanomagnets oriented perpendicular to a flat substrate. Even at a separation of 300 nm, where the field from neighboring pillars is only $\sim$ 1 Oe, the interactions have a significant effect on the switching of the magnets.Comment: 19 pages RevTeX, including 12 figures, clarified discussion of numerical technique

Evaluating the integration of supply chain information systems: A case study

Supply chain management (SCM) is the integrated management of business links, information flows and people. It is with this frame of reference that information systems integration from both intra- and inter-organisational levels becomes significant. Enterprise application integration (EAI) has emerged as software technologies to address the issue of integrating the portfolio of SCM components both within organisations and through cross-enterprises. EAI is based on a diversity of integration technologies (e.g. message brokers, ebXML) that differ in the type and level of integration they offer. However, none of these technologies claim to be a panacea to overcoming all integration problems but rather, need to be pieced together to support the linking of diverse applications that often exist within supply chains. In exploring the evaluation of supply chain integration, the authors propose a framework for evaluating the portfolio of integration technologies that are used to unify inter-organisational and intra-organisational information systems. The authors define and classify the permutations of information systems available according to their characteristics and integration requirements. These, classifications of system types are then adopted as part of the evaluation framework and empirically tested within a case study

Relativistic predictions of spin observables for exclusive proton knockout reactions

Within the framework of the relativistic distorted wave impulse approximation (DWIA), we investigate the sensitivity of complete sets of polarization transfer observables for exclusive proton knockout from the 3s$_{1/2}$, 2d$_{3/2}$ and 2d$_{5/2}$ states in $^{208}$Pb, at an incident laboratory kinetic energy of 202 MeV, and for coincident coplanar scattering angles ($28.0^{\circ}$, $-54.6^{\circ}$), to different distorting optical potentials, finite-range (FR) versus zero-range (ZR) approximations to the DWIA, as well as medium-modified meson-nucleon coupling constants and meson masses. Results are also compared to the nonrelativistic DWIA predictions based on the Schr\"{o}dinger equation.Comment: Submitted for publication to Physicical Review C, 23 pages, 7 figure

Dealing with mobility: Understanding access anytime, anywhere

The rapid and accelerating move towards the adoption and use of mobile technologies has increasingly provided people and organisations with the ability to work away from the office and on the move. The new ways of working afforded by these technologies are often characterised in terms of access to information and people ‘anytime, anywhere’. This paper presents a study of mobile workers that highlights different facets of access to remote people and information, and different facets of anytime, anywhere. Four key factors in mobile work are identified from the study: the role of planning, working in ‘dead time’, accessing remote technological and informational resources, and monitoring the activities of remote colleagues. By reflecting on these issues, we can better understand the role of technology and artefact use in mobile work and identify the opportunities for the development of appropriate technological solutions to support mobile workers

Oxandrolone in trauma patients

Study Objective To determine the effect of oxandrolone administration on nutritional and clinical outcomes after multiple trauma. Design Prospective, randomized, double-blind, placebo-controlled study. Setting. Level 1 trauma center in a university teaching hospital. Patients Sixty-two patients requiring enteral nutrition, 60 of whom completed the study. Intervention Patients were randomized to receive either oxandrolone 10 mg or placebo twice/day for a maximum of 28 days. Measurements and Main Results Total urinary nitrogen, prealbumin, nitrogen balance, total body water, and body cell mass were measured on day 1 of enteral nutrition and then at day 7, day 10, and study exit. Patients were assessed daily for metabolic and infectious complications. The two groups were similar for demographics and dosage of enteral nutrition. Measurement of total urinary nitrogen at study entry showed both groups to be highly catabolic (oxandrolone 17.2 ± 4.9, placebo 19.1 ± 10.8 g/day, NS). On days 7 and 10, total urinary nitrogen increased in both groups; however, there was no significant difference between groups. Nitrogen balance was negative throughout the study in each group. Body cell mass decreased slightly in both groups over the study period. Prealbumin serum concentrations increased significantly in both groups at day 10 and study exit compared with study entry. The groups did not differ significantly for length of hospital stay (oxandrolone 30.8 ± 17.9, placebo 27.0 ± 25.7 days), length of intensive care unit stay (oxandrolone 17.1 ± 7.8, placebo 15.5 ± 9.7 days), and frequency of pneumonia or sepsis (oxandrolone 48, placebo 43 episodes). Conclusion Oxandrolone 20 mg/day does not have obvious benefit in nutritional and clinical outcomes during the first month after multiple trauma

Propagator of a Charged Particle with a Spin in Uniform Magnetic and Perpendicular Electric Fields

We construct an explicit solution of the Cauchy initial value problem for the time-dependent Schroedinger equation for a charged particle with a spin moving in a uniform magnetic field and a perpendicular electric field varying with time. The corresponding Green function (propagator) is given in terms of elementary functions and certain integrals of the fields with a characteristic function, which should be found as an analytic or numerical solution of the equation of motion for the classical oscillator with a time-dependent frequency. We discuss a particular solution of a related nonlinear Schroedinger equation and some special and limiting cases are outlined.Comment: 17 pages, no figure

Faster ocean warming threatens richest areas of marine biodiversity

First published: 07 July 2022The vulnerability of marine biodiversity to accelerated rates of climatic change is poorly understood. By developing a new method for identifying extreme oceanic warming events during Earth's most recent deglaciation, and comparing these to 21st century projections, we show that future rates of ocean warming will disproportionately affect the most speciose marine communities, potentially threatening biodiversity in more than 70% of current-day global hotspots of marine species richness. The persistence of these richest areas of marine biodiversity will require many species to move well beyond the biogeographic realm where they are endemic, at rates of redistribution not previously seen. Our approach for quantifying exposure of biodiversity to past and future rates of oceanic warming provides new context and scalable information for deriving and strengthening conservation actions to safeguard marine biodiversity under climate change.Stuart C. Brown, Camille Mellin, Jorge García Molinos, Eline D. Lorenzen, Damien A. Fordha